1. Field of Invention
The present invention relates to an information storage medium and, in particular, to an optical information storage medium.
2. Related Art
Accompany to the progress of technology and multimedia, the format of data have been not only still image but also animation. Facing to storage requirement of a great amount of digital audio and video information, there are many optical information storage mediums with high storage capacity could be applied to electronic products, such as compact disc (CD), digital video disc (DVD), blue-ray disc (BD), high definition DVD (HD-DVD).
Conventional substrate of the optical information storage medium is made of polycarbonate (PC). DVD includes a first substrate and a second substrate. By pressing a disc stamper onto the first substrate, that will transfer patterns to the first substrate and form a plurality of different size of pits (or grooves) and lands thereon as data read out by laser beam. The second substrate is a reinforced sheet with no data on it. In prior art, the first substrate and the second substrate are all made of PC. There will be 10 billion pieces of disc being cast-off. These disc made by PC could not be self-dissolved and be reused, they will induce environmental pollutions. Besides, burning the disc will release poisonous gases and cause air pollution. Therefore, how to provide an optical information storage medium with low pollution to environment has been an essential target.